A light emitting device, in which a light emitting diode or the like is employed as a light source and a light storing phosphor is provided near the light source, has been known as a conventional technique. According to such a light emitting device, even in a case where the light source stops emitting light, the light storing phosphor can continue to emit.
Patent Literature 1 discloses a display that (i) employs, as a pixel for displaying an image, a light storing phosphor light emitting element and (ii) is capable of continuing to emit light in a desired luminescent color even after a light emitting diode stops emitting light. Note that the light storing phosphor light emitting element is obtained by combining (a) a light emitting diode that emits light in a near ultraviolet region or a visible light region and (b) a light storing phosphor that is capable of instantaneously emitting light upon being excited by light emitted from the light emitting diode. This allows a function, as a display, to be maintained even in a case where the light emitting element, having the light emitting diode, stops emitting light due to some reason.
Patent Literature 2 discloses an illuminating apparatus that includes (i) an LED package having an LED and a phosphor which is arranged so as to cover the LED and (ii) a reflector having a reflective surface for reflecting light emitted from each of the LED and the phosphor, wherein a part in which a light storing material is arranged and a part in which no light storing material is arranged are provided on the reflective surface of the reflector. This allows the illuminating apparatus to (i) irradiate auxiliary light while the LED is being turned off and (ii) reduce a possibility that light reflected from the reflective surface of the reflector is weakened while the LED is being turned on.
Patent Literature 3 discloses a fluorescent substance including (i) a first fluorescent substance which converts at least a part of energy of an excitation source and has a first emission spectrum different from that of such converted energy and (ii) a second fluorescent substance which converts at least a part of the first emission spectrum and has a second emission spectrum different from the first emission spectrum, wherein the first fluorescent substance is a light storing fluorescent substance. It is therefore possible to provide (i) a fluorescent substance which has an extremely wide luminescent chromaticity range and is capable of emitting afterglow having a high luminance and (ii) a lamp including the fluorescent substance.
Patent Literature 4 discloses a light emitter in which a light storing material is incorporated into an optical system of an LED, the light storing material is excited by ultraviolet region energy of the LED, and the light storing material is used as a secondary light source. This allows self-luminous visible light to be obtained without using electric power dedicated for exciting the light storing material, thereby ultimately improving an efficiency of the light emitter.
Patent Literature 5 discloses a light emitting diode that is made up of (i) a light emitting diode chip, (ii) a transparent member which is provided near the light emitting diode chip and transmits light emitted from the light emitting diode chip, and (iii) light storing fluorescent agent particles which are dispersed in the transparent member. This allows, by use of light emitting of stored light, a reduction in electric current consumption during light emitting, and ultimately allows a power-saving light emitting diode to be realized.